1. Field of the Invention
This invention relates to a process of spinning a yarn joined to a previously spun yarn in friction spinning apparatus comprising two juxtaposed, closely spaced apart twisting members, which define a generally triangular space, which tapers to a nip and from which air is sucked. Fibers are supplied to said triangular space and are twisted therein to form a yarn, which is withdrawn by suitable withdrawing means. To join the spun yarn to a previously spun yarn, said previously spun yarn is introduced into the triangular space so that a joint-forming portion of said yarn is disposed in the region to which the fibers are supplied and said previously spun yarn is withdrawn while fibers are supplied to said triangular space so as to contact said joint-forming portion. The invention relates also to spinning apparatus by which said process can be carried out.
2. Description of the Prior Art
When it is desired to spin a yarn which is joined to a previously spun yarn, for instance, after a yarn breakage, in friction spinning apparatus comprising two spinning drums defining a generally triangular space, it is known from (EP-A Nos. 0 034 427) to place a cut end of a previously spun yarn into the triangular space and to withdraw said previously spun yarn from said triangular space while singled staple fibers are supplied to the triangular space so as to contact the previously spun yarn in said space. The fibers are then twisted in contact with the previously spun yarn to form a new yarn, which is withdrawn together with the previously spun yarn. That process of spinning a yarn joined to a previously spun yarn has the disadvantage that the joint between the previously spun and new yarns is thicker and must be aftertreated. Besides, the formation of such joints having the same strength as other portions of said yarns cannot be ensured.
It is known from Laid-open German Application No. 32 47 288 that a previously spun yarn may be provided at one end with a thinned-out fiber tuft, which is a spinning rotor of open-end spinning apparatus pemits an improved spinning of a yarn joined to a previously spun yarn. In accordance with that proposal a portion of the previously spun yarn is gripped between two grippers and is untwisted between said grippers in that one gripper is held against rotation and the other gripper, which is mounted to be freely rotatable, is subjected to a tensile force in the direction of the axis of the yarn. Under the action of that tensile force, which is exerted on the rotatably mounted gripper preferably by means of a weight, a yarn is untwisted and that end portion of the yarn which is gripped by the rotatable gripper is detached from the remaining yarn so that the latter is provided at its rear end with a thinned-out fiber tuft having fiber ends spaced along the yarn. New fibers supplied to the spinning rotor can then be joined to said fiber tuft without a formation of an enlarged joint. That known process of spinning a yarn joined to a previously spun yarn has the disadvantage that separate equipment is required to form the fiber tuft so that the expenditure is greatly increased and a relatively long time is required until spinning can be continued after a yarn breakage because in that case the previously spun yarn cannot be introduced into this spinning rotor until it has been provided with a fiber tuft.